1. Field of the Invention
This invention relates to the use of selected poly(oxyalkylated) hydrazines as corrosion inhibitors in hydraulic fluids.
2. Brief Description of the Prior Art
Poly(oxyalkylated) hydrazines are known compounds. For example, British Pat. No. 987,354, which issued to Farbenfabriken Bayer A.G. on Mar. 24, 1965, teaches that alkylene oxide adducts of hydrazine [e.g., tetra(hydroxypropyl)hydrazine] may be used to prepare cellular polyurethane. However, the art is devoid of any teaching that these adducts may be used as corrosion inhibitors.
Separately, a wide variety of chemical compounds have been disclosed which effectively reduce the corrosive properties of liquids such as hydraulic fluids. These inhibitors are generally added to the corrosive liquids to protect the metals in contact with these liquids. Alternatively, such inhibitors may be applied first to the metal surface, either as is, or as a solution in some carrier liquid or paste.
While many of these corrosion inhibitors have been used successfully for many years, stricter toxicological and other environmental standards are restricting the use of some of the compounds (e.g., chromates and dichromates). Accordingly, there is a need in the art to develop new and effective corrosion inhibitors which do not pose these environmental problems.